Gearboxes, including those used on fire engines, encase various gears used for transferring mechanical power. A drive-shaft gear is often matched with one or more gears to operate various gear shafts. A typical gearbox for a fire engine may house gears from a drive shaft, an idler shaft, and a pump shaft. The gears within a sealed gearbox are surrounded with oil or other lubricant to reduce friction. Gearboxes are specially designed to encase the necessary gears, and are usually constructed of cast aluminum or iron and from a specially designed mold, resulting in a high cost item. During operation the transfer of mechanical power produces heat and friction within the gears, gearbox, and oil or other lubricant. Excessive heat within the gearbox, especially for prolonged periods, can be disastrous, resulting in breakdown of lubricant and failure of the gears, gear exchange, bearings, and gearbox. Thus various efforts have been made to reduce the heat within the gearbox.
One system for reducing the heat within the gearbox is to introduce a coolant source directly within the gearbox. Such system may include use of a copper tube inserted within the gearbox cavity. A coolant such as cool water or other cool liquid is pumped, sometimes continuously, through the copper tube which thereby cools the interior of the gearbox. However, such system requires insertion of copper tubing within the gearbox, and further requires that the cooling fluid be drained from the system for storage. Insertion of the copper tubing requires proper placement and fitting and occupies space within the gearbox. Failure to drain the copper tubing results in a bursting of the copper tubing in cold weather conditions, and may further cause extensive damage to the gears and destruction of the gearbox. If the copper tubing breaks, the gearcase fills with coolant and fails. Freezing is a special concern for fire pumps because many use plain water to cool the gearcase instead of a glycol/water (antifreeze) mixture.
Other systems used for cooling gearbox assemblies use techniques where the heated lubricant or oil is transferred to an external cooler for cooling and then circulated back to the gearbox. Such systems are often too complicated, expensive or inefficient for desired use. Accordingly, it is believed that it would be an improvement to provide a cooling apparatus for a gearbox which does not require insertion of any elements within the gearbox, including insertion of any copper tubing within the gearbox, or reoccurring draining of the coolant liquid. Moreover, it is believed that it would be an improvement to provide a cooling apparatus that effectively cools a gearbox without complicated, expensive or inefficient techniques.